Retailers are facing prosecution following an undercover trading standards check at six Oxfordshire electrical repair shops.

Trading Standard officials selected random businesses as well as those that had already been the subject of comp- laints.

An expert was used to set up faults on appliances such as televisions, video recorders and vacuum cleaners.

One device was then taken to each shop, none of which has been named.

Problems included being charged for parts that had not been replaced or claiming that more components had been used than was the case.

Officers said they were disappointed that problems were found with the service at four of the outlets.

Managers at three of the businesses have been interviewed and could face prosecution if their actions were seriously negligent or malicious.

Such cases can result in a £5,000 fine at magistrates court but an unlimited fine and even imprisonment can follow at crown court.

The fourth proprietor was spoken to and warned, and no further action was taken.

David Sibbert, chief trading standards officer for Oxfordshire, said: "The results of this survey are disappointing for consumers.

"When a job is completed, people have no way of checking the quality or value of what has been done and have to take the matter on trust.

"Our survey shows that this trust can very often be mis- placed. We're investigating these cases and we certainly intend to repeat this exer- cise."

The tests took place over Christmas and the New Year, but the results were only released on Wednesday.

Trading standards officers are now urging consumers to ask for a quotation before agreeing to a repair and to find out the charge for preliminary work.

They should also ask to be shown any components which have been removed, look for retailers who are members of a trade association, heed word-of-mouth advice and shop around.